> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qwedai.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Changelog
> Release notes for the QWED Protocol: version history, new guards, breaking changes, security fixes, and hardening across QWED engines.
All notable changes to the QWED platform, listed by release.
***
## QWED Math Engine — fail-closed on mode ambiguity, eigenvalue cardinality, and IRR convergence
**Released: July 24, 2026** · [Jump to details](#qwed-math-engine--fail-closed-on-mode-ambiguity-eigenvalue-cardinality-and-irr-convergence) · [PR #217](https://github.com/qwed-ai/qwed-verification/pull/217) · [PR #218](https://github.com/qwed-ai/qwed-verification/pull/218) · [PR #219](https://github.com/qwed-ai/qwed-verification/pull/219)
> Three core-verifier fixes tighten the math engine's fail-closed contract. `verify_statistics(statistic="mode")`, `verify_matrix_operation(operation="eigenvalues")`, and `verify_irr()` no longer produce `VERIFIED` when the underlying claim is ambiguous, under-specified, or numerically unproven. Callers see `BLOCKED` or `CORRECTION_NEEDED` with structured diagnostics instead of a best-effort answer.
**Behavior change.** Inputs that previously received `VERIFIED` may now receive `BLOCKED` or `CORRECTION_NEEDED` — treat both as unverified. If your code branched on `result.verified` or `result.status == "VERIFIED"` alone, it will continue to work; if you consumed `calculated`/`calculated_irr`/`calculated_eigenvalues` from a `BLOCKED` result as a fallback, those fields are not present on `BLOCKED` responses. They remain available on `CORRECTION_NEEDED` responses for diagnostic use. Consume the new structured fields (`ambiguous_modes`, `calculated_count`/`claimed_count`, `converged`, `iterations_used`) for richer diagnostics.
### What changed
* **`verify_statistics(statistic="mode")` requires a unique mode.** When two or more values tie for the maximum frequency, the engine returns `BLOCKED` with an `ambiguous_modes` list instead of heuristically picking one. Only a unique mode can produce `VERIFIED`.
* **`verify_matrix_operation(operation="eigenvalues")` requires cardinality match.** The claimed eigenvalue list length must equal the calculated count (counting algebraic multiplicity). Mismatched lengths return `CORRECTION_NEEDED` with `calculated_count`/`claimed_count`. Previously the value comparison used `zip`, which silently truncated to the shorter list.
* **`verify_irr()` requires proof of Newton-Raphson convergence.** `BLOCKED` is now returned when cash flows have more than one sign change (multi-root ambiguity per Descartes' rule), zero sign changes (no real IRR), all-zero cash flows (IRR undefined), the Newton derivative stalls at zero, or the method fails to converge within 100 iterations. Successful results include `converged: true` and `iterations_used`.
### Before and after
**Ambiguous mode**
```python theme={null}
# Before — heuristically picked one of the tied values and could return VERIFIED
client.verify_statistics(statistic="mode", data=[1, 1, 2, 2, 3], expected=1)
# status: "VERIFIED"
# After — BLOCKED with the full list of tied values
client.verify_statistics(statistic="mode", data=[1, 1, 2, 2, 3], expected=1)
# status: "BLOCKED"
# ambiguous_modes: [1, 2]
```
**Incomplete eigenvalue claim**
```python theme={null}
# Before — zip truncated the comparison to length 1 and returned VERIFIED
client.verify_matrix_operation(operation="eigenvalues", matrix=[[2, 0], [0, 3]], expected=[2])
# status: "VERIFIED"
# After — CORRECTION_NEEDED with explicit cardinality diagnostics
client.verify_matrix_operation(operation="eigenvalues", matrix=[[2, 0], [0, 3]], expected=[2])
# status: "CORRECTION_NEEDED"
# calculated_count: 2, claimed_count: 1
# calculated_eigenvalues: [2.0, 3.0]
```
**IRR with multiple sign changes**
```python theme={null}
# Before — Newton-Raphson returned a best-effort iterate that could be VERIFIED
client.verify_irr(cash_flows=[-100, 230, -132], expected=0.10)
# status: "VERIFIED"
# After — BLOCKED because two sign changes admit multiple real IRRs
client.verify_irr(cash_flows=[-100, 230, -132], expected=0.10)
# status: "BLOCKED"
# sign_changes: 2
```
### What this means for you
Existing code that already treated non-`VERIFIED` statuses as unverified continues to work. New policy code should read the structured diagnostic fields on `BLOCKED`/`CORRECTION_NEEDED` results — `ambiguous_modes`, `calculated_count`/`claimed_count`, and `converged`/`iterations_used` — to explain why a claim was rejected and to satisfy audit requirements. See [Math engine — Fail-closed semantics](/engines/math#fail-closed-semantics) for the full state tables and response schemas.
***
## QWED-Finance — v2.1.0 released
**Released: July 22, 2026** · [GitHub PR #40](https://github.com/QWED-AI/qwed-finance/pull/40)
> `qwed-finance` v2.1.0 is now the current release. This is a version-sync release: the Python package, npm wrapper, GitHub Action, and quickstart workflow reference are all realigned so `QWED Finance Guard` reports a single consistent version across PyPI, npm, and SARIF output in GitHub Advanced Security.
### What changed
* **`qwed-finance` Python package is now v2.1.0** on PyPI (`qwed_finance.__version__ == "2.1.0"`).
* **`@qwed-ai/finance` npm package** version bumped to 2.1.0 to match.
* **GitHub Action** auto-syncs its reported version from the installed package — the `QWED Finance Guard` name in workflow logs and the `version` field on SARIF uploads to the GitHub Security tab now both read `2.1.0` instead of a hardcoded `v2.0`.
* **Quickstart `qwed-verify.yml` workflow** is re-pinned from the stale v1.1.4 SHA to the v2.1.0 SHA (`QWED-AI/qwed-finance@19ce969f21d1fc2019da4d89fff23bc108e15a98 # v2.1.0`).
### What this means for you
Upgrade your dependency to pick up the current release:
```bash theme={null}
pip install --upgrade qwed-finance
```
If you run QWED Finance in CI, update the action reference so SARIF findings and workflow-run names line up with the current package:
```yaml theme={null}
- name: Verify banking calculations
uses: QWED-AI/qwed-finance@v2.1.0
```
This is a version-sync patch for the existing v2.1.0 release (May 2026). It contains no new API or guard behavior changes beyond those already shipped in v2.1.0 (Decimal migration, fail-closed enforcement, rate parsing fix). For the original breaking changes, see the [v2.1.0 release notes](/changelog-archive#qwed-finance--v210). See [GitHub Action (CI/CD)](/finance/action) for the updated workflow example.
***
## QWED-UCP — v0.3.0 released
**Released: July 20, 2026** · [GitHub PR #38](https://github.com/qwed-ai/qwed-ucp/pull/38)
> `qwed-ucp` v0.3.0 is now the current release. This version ships the typed `TrustStatus` enum on every verification result, alongside the fail-closed middleware and internal-error handling delivered over the v0.2.x series.
### What changed
* **`qwed-ucp` Python package is now v0.3.0** on PyPI.
* **Express middleware `qwed-ucp-middleware`** package version bumped to match.
* **`TrustStatus` enum** is confirmed as available from v0.3.0 onward — see [Trust status](/ucp/guards#trust-status) for the full state table and usage.
* **GitHub Action** should now be pinned to `QWED-AI/qwed-ucp@v0.3.0`.
### What this means for you
Upgrade your dependency to pick up the current release:
```bash theme={null}
pip install --upgrade qwed-ucp
```
If you audit checkouts in CI, update the action reference:
```yaml theme={null}
- name: Audit Commerce Transactions
uses: QWED-AI/qwed-ucp@v0.3.0
```
Existing code that branches on `result.verified` continues to work unchanged. New code should branch on `result.status` (a `TrustStatus`) to distinguish `FAILED` from `ENGINE_ERROR`, `UNVERIFIABLE`, and other non-`VERIFIED` verdicts.
***
## QWED-UCP — Express middleware fails closed on internal verification errors
**Released: July 18, 2026** · [GitHub PR #36](https://github.com/qwed-ai/qwed-ucp/pull/36)
> When a guard raised an unexpected exception, the Express middleware previously logged the error and called `next()` — letting an unverified checkout through to the downstream handler. That defeated the trust boundary. The `catch` block now short-circuits with `HTTP 500`, `X-QWED-Verified: false`, and `code: "INTERNAL_VERIFICATION_ERROR"` so an internal crash can no longer be mistaken for a passing verification.
### What changed
* **Express middleware `catch` block is now fail-closed.** On any exception raised during `verifyCheckoutLocally()`, the middleware returns:
```json theme={null}
{
"error": "QWED-UCP Verification Failed",
"message": "Internal verification error: verification could not be completed",
"code": "INTERNAL_VERIFICATION_ERROR"
}
```
The underlying exception is logged server-side via `console.error` but is **not** included in the response body — raw stack traces, file paths, and internal messages stay out of client-visible output.
* **`X-QWED-Verified: false`** is set on the 500 response so upstream policy layers can treat it the same as a 422 failure.
* **npm package fix.** `qwed-ucp-middleware.js` is now included in the published `files` array. Previous versions installed via npm were missing the entrypoint that `index.js` required at runtime.
**Behavior change.** Any client code that treated an Express middleware error as a soft pass (e.g. retrying without checking the status, or relying on `next()` being called) will now see a `500`. Treat `500 INTERNAL_VERIFICATION_ERROR` the same as `422 VERIFICATION_FAILED` — the request has **not** been verified and must not be settled.
### What this means for you
Existing integrations that already branched on `X-QWED-Verified` or on the response status keep working — they just start seeing a new `500` path that was previously invisible. New integrations should treat both `4xx` and `5xx` responses from the middleware as an unverified request. See [Express.js middleware — Fail-closed on internal verification errors](/ucp/middleware-express#fail-closed-on-internal-verification-errors) for the full response contract.
***
## QWED-UCP — typed `TrustStatus` enum on every verification result
**Released: July 15, 2026** · [GitHub PR #33](https://github.com/qwed-ai/qwed-ucp/pull/33)
> Verification results previously exposed a single `verified: bool` that collapsed "proof disproved," "proof could not be established," "input outside supported semantics," and "verifier engine crashed" into the same `False` bucket. Every result dataclass now also carries a typed `status: TrustStatus` field so downstream policy code can make trust-aware decisions without parsing error strings.
### What changed
* **New `TrustStatus` enum** exported from `qwed_ucp` with seven states: `VERIFIED`, `FAILED`, `UNVERIFIABLE`, `UNSUPPORTED`, `PARTIAL`, `ENGINE_ERROR`, and `QUARANTINED` (reserved).
* **`status` field on every result** — `GuardResult`, `UCPVerificationResult`, and each per-guard result type (`MoneyGuardResult`, `StateGuardResult`, `SchemaGuardResult`, `LineItemsGuardResult`, `DiscountGuardResult`, `CurrencyGuardResult`, `RefundGuardResult`, `TipGuardResult`, `FeeGuardResult`, `AttestationResult`).
* **`UCPVerifier.verify_checkout()` now surfaces `ENGINE_ERROR`** when any guard raises an exception, instead of silently collapsing to `verified=False`.
* **`verified: bool` is preserved** as a backward-compatible derived field: `result.verified` is `True` only when `result.status == TrustStatus.VERIFIED`. Existing constructors that pass `verified=True`/`verified=False` continue to produce the corresponding `VERIFIED`/`FAILED` status.
### What this means for you
Existing code that reads `result.verified` or constructs results with `verified=...` keeps working unchanged. New policy code should branch on `result.status` to distinguish a disproved proof from a crashed verifier — see [Trust status](/ucp/guards#trust-status) for the full state table and an example.
***
## QWED-UCP — middleware fails closed on empty and non-JSON request bodies
**Released: July 14, 2026** · [GitHub PR #32](https://github.com/QWED-AI/qwed-ucp/pull/32)
> The FastAPI and Express middleware previously forwarded requests with an empty body, malformed JSON, or a non-object JSON payload to the downstream handler without running any guards. On a `/checkout-sessions` route that defeated the trust boundary — an attacker could send `{}`'s worth of nothing and skip verification. Both middlewares now reject those requests with `HTTP 422`, `X-QWED-Verified: false`, and `code: "UNPARSEABLE_REQUEST"` before the handler runs.
### What changed
* **FastAPI:** returns a distinct message per case:
* Empty body → `"Empty request body: cannot verify empty payload"`
* Malformed or non-UTF-8 body → `"Malformed request body: expected JSON"`
* Top-level non-object JSON → `"Invalid request body: expected JSON object"`
* **Express:** all three cases return `"Empty or non-JSON request body: cannot verify unparseable payload"`.
* **Non-protected methods and paths** (for example, `GET /health` or a `POST` to a route outside `verify_paths`) still pass through untouched.
This is a fail-closed behavior change. Any client that was previously reaching a `/checkout-sessions`, `/checkout`, `/cart`, or `/payment` handler with a missing, malformed, or non-object JSON body will now receive `422 UNPARSEABLE_REQUEST` instead. Send checkout payloads as `application/json` with a JSON object at the top level, or narrow `verify_paths` if a route should not be treated as a checkout endpoint.
### What this means for you
If you deploy QWED-UCP as middleware in front of a UCP merchant server, unparseable requests can no longer bypass the guards. See [FastAPI middleware](/ucp/middleware-fastapi#fail-closed-on-unparseable-bodies), [Express.js middleware](/ucp/middleware-express#fail-closed-on-unparseable-bodies), and the [troubleshooting entry](/ucp/troubleshooting#unparseable_request-422-from-middleware) for the exact response shape and how to configure protected paths.
***
## QWED-A2A — persistent signing key and JWKS discovery endpoint
**Released: July 10, 2026** · [GitHub PR #29](https://github.com/QWED-AI/qwed-a2a/pull/29)
> `A2ACryptoService` no longer generates an ephemeral ECDSA P-256 key per process. The signing key is now loaded from the `QWED_A2A_SIGNING_KEY_PEM` environment variable (or the `pem_key` constructor argument) so attestation JWTs issued before a restart remain verifiable afterwards. A new `/.well-known/jwks.json` endpoint publishes the current public key for external consumers.
### What changed
* **Persistent signing key** — `A2ACryptoService` reads an unencrypted PKCS#8 P-256 PEM from `QWED_A2A_SIGNING_KEY_PEM` on first use. The derived `key_id` is a SHA-256 fingerprint of the public key, so it stays stable as long as the PEM does.
* **Fail-closed on missing key** — `sign_verdict`, `verify_attestation`, `get_public_key_jwk`, and `A2AVerificationInterceptor.intercept()` all raise `RuntimeError` when the PEM is missing, malformed, or uses a curve other than `SECP256R1`. The FastAPI gateway surfaces this as `HTTP 503 Signing key unavailable`.
* **JWKS endpoint** — A new `wellknown_router` exposes `GET /.well-known/jwks.json` for downstream services and auditors to fetch the current public key without an out-of-band exchange.
* **`get_public_key_jwk()`** — Returns the current public key as a JWK (`kty`, `crv`, `x`, `y`, `kid`, `use`, `alg`).
### Breaking changes
`A2ACryptoService()` and `A2AVerificationInterceptor()` no longer produce a working signer without configuration. Every deployment must now set `QWED_A2A_SIGNING_KEY_PEM` (and continue to set `QWED_A2A_DEPLOYMENT_ID`) before the service starts. Generate a key with:
```bash theme={null}
openssl ecparam -name prime256v1 -genkey -noout \
| openssl pkcs8 -topk8 -nocrypt \
> qwed_a2a_signing_key.pem
```
Load the PEM into `QWED_A2A_SIGNING_KEY_PEM` from your secrets manager, and make sure every replica in a logical deployment uses the same PEM so their `kid`s match and tokens cross-verify.
### What this means for you
If you deploy the QWED-A2A gateway, you now get audit continuity across restarts and rolling deployments — a JWT signed by an earlier process is still verifiable by the next one, provided the PEM is unchanged. External services can also verify attestations by fetching `/.well-known/jwks.json` directly. See [Crypto attestations](/a2a/crypto-attestations) and [Deployment](/a2a/deployment) for the full setup, JWKS shape, and key rotation guidance.
***
## QWED-Tax — structured 3-layer diagnostics for TDS, ITC, and GST-RCM
**Released: June 21, 2026** · [GitHub PR #45](https://github.com/QWED-AI/qwed-tax/pull/45)
> QWED-Tax adopts the same 3-layer `DiagnosticResult` contract introduced in [QWED-Verification v5.2.0](/changelog#v520--structured-verification-diagnostics) — as an independent model, no cross-package dependency. The first three guards (TDS, Input Tax Credit, GST reverse-charge) now expose a structured diagnostic in addition to their existing dict response.
### What's new
* **Tri-state status** — Every diagnostic resolves to `VERIFIED`, `UNVERIFIABLE`, or `BLOCKED`. No `HEURISTIC` or `AMBIGUOUS` middle ground.
* **Three disclosure layers** — A short agent-safe summary (no statute IDs or detection logic), a structured developer evidence block (constraint ID, statute, jurisdiction, audit trace, deduction, net payable), and an optional proof reference.
* **Proof reference is the authority bit** — A deterministic sha256 hash of the audit trace, present only when a result is `VERIFIED`. Absent on `UNVERIFIABLE` and `BLOCKED`.
* **First migrations** — `TDSGuard`, `InputCreditGuard`, and `GSTGuard` (reverse-charge) each expose the new diagnostic format alongside their existing return shape.
### Compatibility
**Additive release.** The legacy dict API on every guard is unchanged — the diagnostic format is opt-in. Existing integrations continue to work without modification. The remaining nine QWED-Tax guards (CapitalGains, Classification, Speculation, Setoff, Crypto, Valuation, Remittance, PoEM, Withholding) will migrate in follow-up releases.
### What this means for you
If you've already adopted the QWED-Verification diagnostic contract, the same response shape now applies to TDS, ITC, and GST-RCM checks — including the proof-reference authority bit you can gate execution on. See the [Verification Diagnostics guide](/advanced/diagnostics) for the response shape and the [tax guards reference](/tax/guards) for guard-by-guard coverage.
***
## QWED-Tax — exact paise comparison, edge-case input rejection, and strict payload schemas
**Released: June 21, 2026** · [GitHub PR #44](https://github.com/QWED-AI/qwed-tax/pull/44)
> Three input-strictness fixes ship together. `CryptoTaxGuard.verify_flat_tax_rate` now compares quantized paise values exactly instead of within a 0.1 tolerance, `ValuationGuard` and `RemittanceGuard` reject the edge-case numeric inputs that previously slipped through, and every QWED-Tax Pydantic input model now forbids unexpected fields.
### What changed
* **`CryptoTaxGuard.verify_flat_tax_rate`** — The `Decimal("0.1")` tolerance was removed. Both the computed `expected_tax` and the caller's `claimed_tax` are now quantized to two decimal places using `ROUND_HALF_UP` and compared with an exact `==`. A 1-paise (`0.01`) deviation correctly returns `verified=False`.
* **`ValuationGuard.verify_conversion`** — Added explicit range checks: `discount` must be in `[0, 1)`, and `cap`, `next_round_price`, and `investment` must all be strictly positive. `DivisionByZero` is now caught alongside `InvalidOperation` so a degenerate `cap = 0` or `discount = 1` no longer crashes — it fails closed with a structured `{"verified": False, "error": "..."}` response. The previous behavior allowed a `discount > 1` to produce a negative share count.
* **`RemittanceGuard.verify_lrs_limit`** — After numeric parsing, `amount_usd` and `financial_year_usage` are now checked for negativity. Negative inputs return `{"verified": False, "error": "BLOCKED: ..."}` instead of being summed into the limit check, where a negative usage could mask a transaction that exceeds the \$250,000 LRS cap.
* **Input models** — `Address`, `WorkArrangement`, `WorkerClassificationParams`, `ContractorPayment`, `TaxEntry`, `DeductionEntry`, `PayrollEntry`, and `VerificationResult` are now configured with `model_config = ConfigDict(extra="forbid")`. Any payload with an unexpected key raises a Pydantic `ValidationError` at the boundary. `QWEDTaxMiddleware` already surfaces this as `status: "BLOCKED"` with `risk: "INVALID_PAYLOAD"`.
### Breaking changes
Callers that previously relied on the 0.1-rupee tolerance in `CryptoTaxGuard.verify_flat_tax_rate` will now receive `verified=False` for claims that differ from `vda_income * 0.30` by 1 paise or more. Round your claimed tax to two decimal places with `ROUND_HALF_UP` before calling the guard.
```python theme={null}
from decimal import Decimal, ROUND_HALF_UP
claimed = (vda_income * Decimal("0.30")).quantize(Decimal("0.01"), rounding=ROUND_HALF_UP)
```
Payloads sent through `QWEDTaxMiddleware` (or constructed directly with the QWED-Tax input models) that include keys outside the declared schema now raise `ValidationError`. Strip unknown fields from AI-generated output — including typos and speculative overrides like `"override_verification": true` — before invoking the middleware.
`ValuationGuard.verify_conversion` no longer returns a result for `cap <= 0`, `next_round_price <= 0`, `investment <= 0`, `discount < 0`, or `discount >= 1`. These inputs now return `{"verified": False, "error": "..."}` instead of crashing or producing nonsensical share counts.
### What this means for you
If your agent forwards Indian VDA tax claims, startup conversion math, or LRS remittance requests through QWED-Tax, audit the calling code for: (1) tax claims that aren't pre-quantized to two decimal places, (2) discount/cap/investment inputs that can legitimately be zero or out of range, (3) negative remittance amounts being passed defensively, and (4) AI payloads that include fields not declared on the QWED-Tax input models. See the [CryptoTaxGuard](/tax/guards#cryptotaxguard-sec-115bbh), [ValuationGuard](/tax/guards#valuationguard), [RemittanceGuard](/tax/guards#remittanceguard), and [middleware integration guide](/tax/integration#qwedtaxmiddleware-gusto-interceptor) for the updated contracts.
### Audit reference
| Issue | Area | Fix |
| ----- | ------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------- |
| #20 | `CryptoTaxGuard` accepted claims within a 0.1-rupee tolerance | Quantize to paise with `ROUND_HALF_UP`, compare with exact `==` |
| #21 | `ValuationGuard` and `RemittanceGuard` accepted edge-case numeric inputs | Range checks on discount/cap/investment; negativity checks on LRS amount and usage; `DivisionByZero` caught |
| #22 | Input models silently accepted unexpected fields | `model_config = ConfigDict(extra="forbid")` on all eight input models |
***
## QWED-Tax — middleware never returns full "verified" and ReciprocityGuard no longer always-passes
**Released: June 21, 2026** · [GitHub PR #43](https://github.com/QWED-AI/qwed-tax/pull/43)
> Two fail-closed fixes ship together. The Gusto interceptor middleware no longer overstates a gross-to-net arithmetic pass as full tax verification, and `ReciprocityGuard` no longer returns `verified=True` for arrangements with no reciprocity agreement.
`ARITHMETIC_VERIFIED` is a **pre-conformance middleware-layer status**, not part of the `DiagnosticResult` tri-state vocabulary (`VERIFIED` / `UNVERIFIABLE` / `BLOCKED`) introduced in v5.2.0. The middleware will migrate to `DiagnosticResult` when engine-conformance work lands. Until then, treat `ARITHMETIC_VERIFIED` as a distinct middleware signal — it is not equivalent to `VERIFIED`.
### What changed
* **`QWEDTaxMiddleware.process_ai_payroll_request`** — The success response is now `status: "ARITHMETIC_VERIFIED"` with `execution_permitted: false`. The middleware only verifies gross-to-net math; classification, withholding legality, reciprocity, and filing checks are still required before execution. The response includes `checks_run` (what was verified) and `checks_not_run` (what is still required) so callers can decide what to run next.
* **`TaxPreFlight` report** — Every report now includes a `checks_not_run` list covering both unselected guards and **known gaps** (checks not yet implemented for the action). For example, `action="hire"` reports `payroll_arithmetic`, `withholding_legality`, `reciprocity`, and `filing_obligations` as known gaps.
* **`ReciprocityGuard`** — The Z3 solver was removed (the prior expression was tautologically satisfiable and ignored the `same_state` parameter). The guard is now a deterministic lookup against the reciprocity-pair table with explicit fail-closed paths: same state → verified, known pair → verified, no agreement → `verified=False`, unknown state → `verified=False`. A new `verify_reciprocity(residence_state, work_state, same_state=None)` method takes string inputs; `determine_withholding_state(arrangement)` is kept for backwards compatibility.
The reciprocity-pair table covers only the pairs modeled within the `State` enum's 8-state scope (NJ, PA, MD, VA). Pennsylvania has additional reciprocity agreements (with IN, MI, OH, VA, WV, WI) that are not modeled here because those states are not in the enum. VA-PA in particular is a known gap — callers will receive `verified=False` for that pair until the enum and table are extended.
### Breaking changes
The middleware no longer returns `status: "VERIFIED"` or `execution_permitted: true`. Any caller that gated execution on `decision["status"] == "VERIFIED"` or `decision["execution_permitted"]` being truthy will now always block. Update your integration to handle `ARITHMETIC_VERIFIED` and run the checks listed in `checks_not_run` (worker classification, withholding legality, reciprocity, filing) before forwarding to Gusto/Avalara.
`ReciprocityGuard` no longer returns `verified=True` for state pairs without a reciprocity agreement. Callers that previously relied on a Z3-backed "always sat" result for, e.g., NJ → NY will now correctly receive `verified=False`. Route these to your withholding logic for the work state or to human review.
### What this means for you
If your agent forwards payroll payloads to Gusto/Avalara based on a `VERIFIED` status from the middleware, those calls will start blocking until you run the remaining guards (`ClassificationGuard`, `WithholdingGuard`, `ReciprocityGuard.verify_reciprocity`, `Form1099Guard`) yourself. See the [tax integration guide](/tax/integration#qwedtaxmiddleware-gusto-interceptor) for the updated response shape and the [ReciprocityGuard reference](/tax/guards#reciprocityguard-state-tax) for the new lookup contract.
### Audit reference
| Issue | Area | Fix |
| ----- | --------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------- |
| #19 | Middleware overstated partial verification as full verification | Status narrowed to `ARITHMETIC_VERIFIED`, `execution_permitted` forced to `false`, `checks_run`/`checks_not_run` surfaced |
| #40 | `ReciprocityGuard` Z3 solver always returned sat | Z3 removed; deterministic lookup with explicit fail-closed branches |
***
## QWED-Tax — fail-closed on ambiguous classification and unverified claims
**Released: June 21, 2026** · [GitHub PR #42](https://github.com/QWED-AI/qwed-tax/pull/42)
> Six more QWED-Tax guards now refuse to sign off when they can't independently prove a result. Ambiguous worker classifications, unparseable trade dates, unknown set-off heads, and reverse-charge inputs the guard doesn't recognize all return `verified=False` with a structured error instead of a quiet pass.
### Bug fixes
* **CapitalGainsGuard** — Unparseable acquisition or disposal dates and unknown asset types now block instead of being coerced into a sentinel value that flowed through to `verified=True`. SLAB-rate verification can no longer succeed without an income bracket — slab rates can't be proven from the claim alone.
* **ClassificationGuard** — Mixed employee/contractor signals now return `verified=False` with an "ambiguous classification" error. The guard only returns `CONTRACTOR` when no employee indicators are present.
* **SpeculationGuard** — Set-off verification now requires a known income source (`intraday`, `f&o`, `futures`, `options`, `delivery`, `business`, `capital_gains`). Unrecognized sources are blocked instead of silently treated as non-speculative.
* **InterHeadAdjustmentGuard** — Set-off eligibility now runs against an explicit allowlist of heads. Salary loss set-off is added to the prohibition matrix, and unknown heads are blocked rather than defaulting to allow.
* **GSTGuard (RCM)** — Unrecognized service or entity types in reverse-charge checks now surface as a `verified=False` error naming the unknown value, instead of being coerced to `OTHER` or `INDIVIDUAL` and potentially suppressing a statutory RCM obligation. The verifier also gained an optional claim parameter — when you pass a `claimed_is_rcm` value, the guard compares it to the computed result and only returns `verified=True` on an exact match. Calls without the claim get a `computed_only=True` flag so calculation and verification are no longer conflated.
* **CryptoTaxGuard** — Zero VDA income now verifies a claimed tax of zero, instead of returning `verified=True` regardless of claim. Negative VDA income (a loss) returns `verified=False` with a message directing the caller to use `verify_set_off` for loss treatment — the method does not internally invoke `verify_set_off`, so callers must handle the `verified=False` branch explicitly.
### What this means for you
If your agent relied on any of these guards returning `verified=True` for inputs they don't model — ambiguous worker status, unknown set-off heads, unrecognized RCM service types, or capital-gains transactions with malformed dates — those calls now block. Surface the error to a human reviewer or extend the guard's configured rules before re-running.
See the [QWED-Tax guards reference](/tax/guards) for the updated contracts on each guard.
***
## QWED-Tax — fail-closed on unknown tax rules
**Released: June 19, 2026**
> Tax guards no longer silently pass when they encounter a service, asset, jurisdiction, or payment type they don't model. Six guards now return `verified=False` with a structured error instead of an unsafe default.
### What changed
* **TDSGuard** — unrecognized payment categories no longer return "verified, zero deduction." This closes a path where an agent could classify a payment into an unknown bucket and have it execute with no withholding. `TaxPreFlight` now blocks these payments.
* **CapitalGainsGuard** — unknown asset class or holding term fails closed instead of returning "no hard constraint."
* **NexusGuard** — states not in the configured risk list now require manual review instead of being treated as low-risk.
* **AddressGuard** — unknown state codes fail closed with "manual review required" instead of "assumed valid."
* **Form1099Guard (US)** — unmodeled payment types return `filing_required=None` with a manual-determination flag, instead of defaulting to "no filing required."
* **InputCreditGuard (GST)** — `verified=True` remains the legal default (ITC is allowed unless specifically blocked), but unknown categories now carry an explicit `unverified_category=True` flag in the result and an `audit_trace` entry of `category_match: "default_allow"` so downstream consumers can distinguish known-eligible from default-allowed.
### What this means for you
If your agent currently relies on a `verified=True` response for inputs the guards don't model, those calls will start blocking. Add explicit rules for the categories you care about, or route unverified results to human review.
See the [tax guards reference](/tax/guards) and [tax integration guide](/tax/integration) for the updated contracts.
***
## QWED-Infra — ecosystem policy framework adopted
**Released: June 17, 2026**
> `qwed-infra` now ships with the shared QWED governance baseline: `QWED_RULES.md`, contributor guidance, PR template, CodeRabbit config, and a boundary-check workflow that is consistent with the other QWED repositories.
No runtime behavior changes. Affects contributors and anyone consuming the repository's CI.
***
## QWED-MCP — boundary-check parity with QWED-Infra
**Released: June 18, 2026**
> The `qwed-mcp` boundary-check tool now catches the same import-alias, module-alias, wildcard-import, `eval`/`exec` alias, and `shell=True` patterns that `qwed-infra` does, and fails closed when the scan root is missing.
### What this means for you
If you run `qwed-mcp` boundary checks in CI, expect to catch additional bypass patterns that previously slipped through. Existing passing scans should continue to pass; previously hidden findings may now surface as failures.
See the [MCP tools reference](/mcp/tools) for the current rule set.
***
## QWED Open Responses v0.3.0 — version sync and dependency fix
**Released: June 12, 2026**
> Aligns `qwed-open-responses` with the rest of the QWED package versions and patches a transitive `qs` CVE flagged by Dependabot.
No API changes. Upgrade to pick up the dependency fix.
***
## v5.2.0 — Structured Verification Diagnostics
**Released: June 19, 2026** · [GitHub Release](https://github.com/QWED-AI/qwed-verification/releases/tag/v5.2.0) · Minor
> Introduces the unified 3-layer `DiagnosticResult` model — the diagnostic contract that all QWED verification engines will conform to. This is an **additive** release: no existing engine return types are changed. Engine conformance is tracked in blocked issues (#129, #130, #131, #133, #134, #162, #163, #164, #190, #205).
### New: `DiagnosticResult` model
Three disclosure layers:
* **Layer 1 — Agent-Safe**: `agent_message: str` — agent/model-facing summary, no internals leaked
* **Layer 2 — Developer**: `developer_fields: dict` — structured evidence (`constraint_id`, `advisory_checks`, `methods_used`, evidence)
* **Layer 3 — Proof**: `proof_ref: Optional[str]` — sha256 hash of retained proof artifact; the authority bit
### Key design
* **Tri-state status** — `VERIFIED` / `UNVERIFIABLE` / `BLOCKED` only. No `HEURISTIC` or `AMBIGUOUS` proliferation; richer distinctions live in `developer_fields.constraint_id`
* **`proof_ref` is the authority bit** — present = admissible for control flow, None = reject. No separate `authoritative` boolean needed (resolves #190 design debate)
* **VERIFIED requires proof** — structurally enforced in `__post_init__`; "VERIFIED without proof" is impossible to construct
* **Frozen dataclasses** — `DiagnosticResult` and `AdvisoryCheck` are `frozen=True`; post-construction mutation blocked
* **Advisory checks never influence verdicts** — `AdvisoryCheck.advisory_only=True` enforced via `__post_init__`
* **`compute_proof_ref()`** — deterministic sha256 hashing of JSON-serialized evidence
* **`from_legacy_dict()`** — migration helper for ad-hoc engine dicts (fail-closed states only; raises for legacy VERIFIED)
### Version propagation
| Artifact | Previous | This release |
| -------------------- | -------- | ------------ |
| `qwed` (PyPI) | 5.1.2 | 5.2.0 |
| `qwed_sdk` (Python) | 5.1.1 | 5.2.0 |
| `@qwed-ai/sdk` (npm) | 5.1.2 | 5.2.0 |
| `qwed` (Rust crate) | 5.1.2 | 5.2.0 |
| API version marker | 5.1.2 | 5.2.0 |
| K8s deployment image | 5.1.2 | 5.2.0 |
### Tests
83 new tests covering: status taxonomy, all 3 layers, authority contract, fail-closed enforcement, advisory checks, proof hashing determinism, serialization round-trip, legacy migration, frozen dataclass immutability, and realistic scenarios drawn from the 10 blocked issues.
### Compatibility
**Additive release.** No breaking changes. Existing `VerificationResult` dataclasses and ad-hoc engine dicts continue to work. `DiagnosticResult` is opt-in — engines migrate incrementally.
### Included PRs
* [#206](https://github.com/QWED-AI/qwed-verification/pull/206) — feat(diagnostics): unified 3-layer DiagnosticResult model (#204)
* [#207](https://github.com/QWED-AI/qwed-verification/pull/207) — release: v5.2.0 version propagation
See the [Verification Diagnostics guide](/advanced/diagnostics) for full API documentation.
***
Older entries: [Changelog Archive](/changelog-archive)